U.S. patent number 8,981,727 [Application Number 13/476,165] was granted by the patent office on 2015-03-17 for method and apparatus for charging multiple energy storage devices.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is Robert Dean King, Ruediger Soeren Kusch. Invention is credited to Robert Dean King, Ruediger Soeren Kusch.
United States Patent |
8,981,727 |
Kusch , et al. |
March 17, 2015 |
Method and apparatus for charging multiple energy storage
devices
Abstract
An electric vehicle includes a controller configured to receive
sensor feedback from a high voltage storage device and from a low
voltage storage device, compare the sensor feedback to operating
limits of the respective high and low voltage storage device,
determine, based on the comparison a total charging current to the
high voltage storage device and to the low voltage storage device
and a power split factor of the total charging current to the high
voltage device and to the low voltage device, and regulate the
total power to the low voltage storage device and the high voltage
storage device based on the determination.
Inventors: |
Kusch; Ruediger Soeren (Clifton
Park, NY), King; Robert Dean (Schenectady, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kusch; Ruediger Soeren
King; Robert Dean |
Clifton Park
Schenectady |
NY
NY |
US
US |
|
|
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
49580788 |
Appl.
No.: |
13/476,165 |
Filed: |
May 21, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130307489 A1 |
Nov 21, 2013 |
|
Current U.S.
Class: |
320/134; 320/167;
320/135; 320/162; 320/136 |
Current CPC
Class: |
B60L
15/007 (20130101); H02J 7/0013 (20130101); B60L
50/16 (20190201); B60L 58/20 (20190201); B60L
50/40 (20190201); B60L 58/26 (20190201); B60L
53/22 (20190201); B60L 53/14 (20190201); B60L
53/00 (20190201); B60L 58/21 (20190201); B60L
53/11 (20190201); H02J 7/007 (20130101); B60L
58/12 (20190201); B60L 58/25 (20190201); B60L
2240/549 (20130101); B60L 2240/526 (20130101); Y02T
10/64 (20130101); B60L 2240/547 (20130101); Y02T
10/72 (20130101); Y02T 90/12 (20130101); Y02T
10/7072 (20130101); B60L 2210/10 (20130101); B60L
2240/527 (20130101); Y02T 10/70 (20130101); B60L
2240/545 (20130101); Y02T 90/14 (20130101); B60L
2240/529 (20130101) |
Current International
Class: |
H02J
7/00 (20060101) |
Field of
Search: |
;320/134-136,153,162,166-167 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Shu-Mei et al., "Study of Hybrid Energy Control Strategy for Hybrid
Electric Drive System in All Electric Combat Vehicles", IEEE
Vehicle Power and Propulsion Conference (VPPC), Sep. 3-5, 2008,
Harbin, China, pp. 1-5. cited by applicant .
Liu et al., "Constant SOC Control of a Series Hybrid Electric
Vehicle with Long Driving Range", Proceedings of the 2010 IEEE
International Conference on Information and Automation, Jun. 20-23,
2010, Harbin, China, pp. 1603-1608. cited by applicant.
|
Primary Examiner: Dinh; Paul
Attorney, Agent or Firm: Ziolkowski Patent Solutions Group,
SC Testa; Jean K.
Claims
What is claimed is:
1. An electric vehicle comprising: a controller configured to:
receive sensor feedback from a high voltage storage device and from
a low voltage storage device; compare the sensor feedback to
operating limits of the respective high and low voltage storage
device; determine, based on the comparison: a total charging
current to the high voltage storage device and to the low voltage
storage device; and a power split factor of the total charging
current to the high voltage storage device and to the low voltage
storage device; and regulate the total power to the low voltage
storage device and the high voltage storage device based on the
determination.
2. The system of claim 1 comprising an energy storage and
management system (ESMS) comprising: a plurality of energy ports,
ESMS comprising a plurality of DC electrical converters, each DC
electrical converter configured to step up and to step down a DC
voltage, wherein: a first port of the plurality of energy ports is
a high voltage port couplable to stepped-up voltage sides of each
of the DC electrical converters; a second port of the plurality of
energy ports is a low voltage port couplable to stepped-down
voltage sides of each of the DC electrical converters; and at least
one of the plurality of energy ports is coupleable to an electrical
charging system; the high voltage storage device coupled to the
first port; the low voltage storage device coupled to the second
port; and an electrical charging system coupled to one of the
plurality of energy ports.
3. The system of claim 2 wherein the electrical charging system is
an auxiliary power unit positioned on the electric vehicle and
configured to output electrical power to the power electronic
conversion system while the vehicle is in motion.
4. The system of claim 2 wherein the controller is configured to:
determine a voltage of each of the plurality of energy ports;
determine the power split factor based on the determined voltages
of each respective energy port.
5. The system of claim 1 wherein the controller is configured to:
continuously receive the sensor feedback from the high and from the
low voltage storage devices; compare the continuously received
sensor feedback to the operating limits of the respective high and
low voltage storage devices; revise the determined total charging
current and the power split factor; and regulate power to the low
voltage storage device and the high voltage storage device based on
the revised determination.
6. The system of claim 1 wherein the controller is configured to
determine the power split factor such that, when regulating power
to the high voltage and to the low voltage storage devices, power
is directed to only one of the high and low voltage storage
devices.
7. The system of claim 1 wherein the operating limits of the
respective high and low voltage storage devices are comprised of at
least one of an electrical current limit and a maximum temperature
corresponding to each of the respective high and low voltage
storage devices.
8. The system of claim 1 wherein the controller is configured to
regulate a fan positioned to blow air over one of the high and the
low voltage storage devices bases on the sensor feedback.
9. The system of claim 1 comprising a power device coupled to the
high voltage storage device and the low voltage storage device,
wherein the power device comprises one of a vehicle drivetrain, an
uninterrupted power supply, a mining vehicle drivetrain, a mining
apparatus, a marine system, and an aviation system.
10. A method of managing an energy storage system for an electric
vehicle comprising: receiving sensor feedback from a high voltage
energy storage device of the electric vehicle; comparing the sensor
feedback from the high voltage energy storage device to an
operating limit specific to the high voltage energy storage device;
receiving sensor feedback from a low voltage energy storage device
of the electrical vehicle; comparing the sensor feedback from the
low voltage energy storage device to an operating limit specific to
the low voltage energy storage device; determining, based on the
comparison from the high voltage energy storage device and from the
low voltage energy storage device: a total charging current to the
high voltage energy storage device and to the low voltage energy
storage device; and a power split factor of the total charging
current to the high voltage energy storage device and to the low
voltage energy storage device; and regulating the total power to
the low voltage energy storage device and the high voltage energy
storage device based on the determination.
11. The method of claim 10 comprising obtaining energy storage
device parameter information and determining the total charging
current and the power split factor based on the energy storage
device parameter information, wherein the energy storage parameter
information includes a state of charge and current operating
voltage corresponding to each of the respective high and low
voltage energy storage devices.
12. The method of claim 10 wherein the operating limits for the
high voltage energy storage device and the low voltage energy
storage device include at least one of an electrical current limit
and a maximum temperature corresponding to each of the respective
high and low voltage energy storage devices.
13. The method of claim 10 comprising regulating the total power to
the low voltage energy storage device and the high voltage energy
storage device from an auxiliary power unit that is positioned on
the electric vehicle.
14. The method of claim 10 wherein the high voltage energy storage
device is a power battery having an operational voltage at 400 V or
greater, and the low voltage energy storage device is one of an
energy battery and an ultracapacitor having an operational voltage
at 120 V or less.
15. A non-transitory computer readable storage medium coupled to an
energy storage and management system (ESMS) of an electric vehicle
(EV) and having stored thereon a computer program comprising
instructions which when executed by a computer cause the computer
to: receive sensor feedback from a high voltage energy storage
device of the EV and from a low voltage energy storage device of
the EV; compare the sensor feedback to operating limits of the
respective energy storage devices; determine, based on the
comparison: a total charging current to the energy storage devices;
and a power split factor of the total charging current between the
high voltage energy storage device and the low voltage energy
storage device; and regulate the total power to the energy storage
devices based on the determination.
16. The non-transitory computer readable storage medium of claim 15
wherein computer is further caused to regulate the total power to
the energy storage devices from an auxiliary unit positioned on the
EV and coupled to a port of the ESMS.
17. The non-transitory computer readable storage medium of claim 15
wherein the computer is further caused to determine a voltage of
each of a plurality of energy ports of the ESMS, and determine the
power split factor based on the determined voltages of each
respective energy port.
18. The non-transitory computer readable storage medium of claim 15
wherein the computer is further caused to: continuously receive the
sensor feedback from the high and from the low voltage energy
storage devices; compare the continuously received sensor feedback
to the operating limits of the respective high and low voltage
energy storage devices; revise the determined total charging
current and the power split factor; and regulate the total power to
the energy storage devices based on the revision.
19. The non-transitory computer readable storage medium of claim 15
wherein the operating limits of the respective high and low voltage
energy storage devices are comprised of at least one of an
electrical current limit and a maximum temperature corresponding to
each of the respective high and low voltage energy storage
devices.
20. The non-transitory computer readable storage medium of claim 15
wherein the computer is further caused to regulate a fan positioned
to blow air over one of the high and the low voltage energy storage
devices bases on the sensor feedback.
21. The method of claim of claim 10 comprising: coupling the high
voltage energy storage device to a first port of a plurality of
energy ports of an energy storage and management system (ESMS),
wherein the first port is a high voltage port coupleable to
stepped-up voltage sides of each of a plurality of DC electrical
converters; coupling the low voltage energy storage device to a
second port of the plurality of energy ports of the ESMS, wherein
the second port is a low voltage port coupleable to stepped-down
voltage sides of each of the plurality of DC electrical converters;
and coupling an electrical charging system to one of the plurality
of energy ports of the ESMS.
Description
BACKGROUND OF THE INVENTION
Embodiments of the invention relate generally to electric drive
systems including hybrid and electric vehicles and, more
particularly, to charging energy storage devices of an electric
vehicle using a multiport energy management system.
Hybrid electric vehicles may combine an internal combustion engine
and an electric motor powered by an energy storage device, such as
a traction battery, to propel the vehicle. Such a combination may
increase overall fuel efficiency by enabling the combustion engine
and the electric motor to each operate in respective ranges of
increased efficiency. Electric motors, for example, may be
efficient at accelerating from a standing start, while internal
combustion engines (ICEs) may be efficient during sustained periods
of constant engine operation, such as in highway driving. Having an
electric motor to boost initial acceleration allows combustion
engines in hybrid vehicles to be smaller and more fuel
efficient.
Purely electric vehicles use stored electrical energy to power an
electric motor, which propels the vehicle and may also operate
auxiliary drives. Purely electric vehicles may use one or more
sources of stored electrical energy. For example, a first source of
stored electrical energy may be used to provide longer-lasting
energy, such as a low-voltage battery (commonly referred to as an
`energy battery`) while a second source of stored electrical energy
may be used to provide higher-power energy for, for example,
vehicle acceleration, using a high-voltage battery (commonly
referred to as a `power battery`). Known energy storage devices may
also include an ultracapacitor, which tends to have fast charging
and discharging capability and provides long life operation.
Plug-in electric vehicles, whether of the hybrid electric type or
of the purely electric type, are typically configured to use
electrical energy from an external source to recharge the energy
storage devices. Such vehicles may include on-road and off-road
vehicles, golf carts, neighborhood electric vehicles, forklifts,
and utility trucks as examples. Known charging devices include a
multiport energy storage management system (ESMS) for charging both
low voltage and high voltage energy storage systems of an electric
vehicle. Typically, an ESMS includes buck-boost converters which
can be used in conjunction with one another in order to flexibly
apply charging voltages to a variety of devices having different
charging voltage requirements. An ESMS also typically includes a
high voltage side and a low voltage side. In one known ESMS device
having four ports, two of the ports are on a high voltage side of
the device and two of the ports are on a low voltage side of the
device. The high voltage side is typically used for charging from a
utility grid or renewable energy source (one port on the high
voltage side) and for providing charging power to a power battery
(another port on the high voltage side). The low voltage side is
typically used for charging low voltage devices such as energy
batteries and ultracapacitors of the electric vehicle (ports on the
low voltage side) and may, in some embodiments, also include
adaptability to a low voltage charging source as well, in one of
the low voltage ports.
A power battery, incidentally, is typically included in order to
provide high power bursts for acceleration of the vehicle, as
opposed to an energy battery, which is typically included in order
to provide long-range cruising energy to the vehicle and it is
therefore desirable to operate as a high voltage device. Thus,
because of the high power requirements of the power battery, high
voltage energy storage devices such as power batteries typically
operate under a high voltage operation of 400 V or more, while low
voltage energy storage devices such as energy batteries typically
provide high energy storage and operate at a much lower nominal
voltage, such as 120 V or below. Ultracapacitors can be used in
either high or low voltage applications and thus can be included on
either the high side or the low side of the ESMS charging device,
depending on their type of use (high bursts of power vs. energy
storage for cruising).
Because of the buck-boost converters in the ESMS, multiple
arrangements of energy storage devices and power sources may be
utilized in order to charge the energy storage devices. That is, a
known ESMS is flexibly configurable in that a charging voltage may
be first bucked down, and then boosted up to a desired charging
voltage on the high voltage side. And, because of the bucking and
subsequent boosting operations, the charging on the high side may
be either above or below the charging voltage provided externally.
Similarly, the charging voltage may be bucked to the lower voltage
of the low voltage side as well. Further, because of the multiple
buck-boost converters in an EMS, the charging voltage may be
simultaneously provided to charge both the high voltage device on
the high side, as well as one or more low voltage devices on the
low side. That is, a single high voltage supply may be split to
simultaneously provide energy to the high side and the low side
devices, or to two low side devices, as examples.
Known devices that split power for charging multiple energy storage
devices are typically optimized based simply on a condition of the
devices that are being charged. That is, known charging or ESMS
devices typically base their power split on factors such as the
state-of-charge of the device(s) and/or the voltage at each
respective charging port. Although such an optimization often can
be adequate to provide a maximum overall rate of charging to the
combination of devices being charged, such a charging scheme does
not take into account additional factors such as the overall
implications to the life of the devices themselves that are being
charged, their temperature limits, and the like. That is, although
energy storage devices may be physically capable of receiving a
high rate of charge in order to minimize charging time of all
devices, it may not be desirable to do so if the long-term cost to
one or more of the devices is a drop in life.
In other words, the lifecycle cost and eventual need to replace
storage devices such as power batteries, energy batteries, and
ultracapacitors may not be worth the marginal decrease in charging
time when charging is based on a state-of-charge alone. In fact,
because known charging devices determine power splits and charging
rates without taking into account the specifics of the devices
themselves (but rather are simply based on a state-of-charge or a
voltage at the charging terminals), the devices not only have a
longtime risk of life, but are also at risk of catastrophic failure
if charged beyond a rate than the device can handle.
It would therefore be desirable to provide an apparatus and control
scheme to optimize overall recharge time for multiple energy
storage devices of an EV while taking into account the life
implications of the charging scheme.
BRIEF DESCRIPTION OF THE INVENTION
The invention is a method and apparatus for optimizing a total
recharge time for multiple energy storage devices of an EV,
accounting for life implications to the energy storage devices
themselves.
According to one aspect of the invention, an electric vehicle
includes a controller configured to receive sensor feedback from a
high voltage storage device and from a low voltage storage device,
compare the sensor feedback to operating limits of the respective
high and low voltage storage device, determine, based on the
comparison a total charging current to the high voltage storage
device and to the low voltage storage device and a power split
factor of the total charging current to the high voltage device and
to the low voltage device, and regulate the total power to the low
voltage storage device and the high voltage storage device based on
the determination.
In accordance with another aspect of the invention, a method of
managing an energy storage system for an electric vehicle includes
receiving sensor feedback from a high voltage energy storage device
of the electric vehicle, comparing the sensor feedback from the
high voltage energy storage device to an operating limit specific
to the high voltage energy storage device, receiving sensor
feedback from a low voltage energy storage device of the electrical
vehicle, comparing the sensor feedback from the low voltage energy
storage device to an operating limit specific to the low voltage
energy storage device, determining, based on the comparison from
the high voltage device and from the low voltage device a total
charging current to the high voltage storage device and to the low
voltage storage device and a power split factor of the total
charging current to the high voltage device and to the low voltage
device, and regulating the total power to the low voltage storage
device and the high voltage storage device based on the
determination.
In accordance with yet another aspect of the invention, a computer
readable storage medium coupled to an energy storage and management
system (ESMS) of an electric vehicle (EV) and having stored thereon
a computer program comprising instructions which when executed by a
computer cause the computer to receive sensor feedback from a high
voltage energy storage device of the EV and from a low voltage
energy storage device of the EV, compare the sensor feedback to
operating limits of the respective energy storage devices,
determine, based on the comparison a total charging current to the
energy storage devices and a power split factor of the total
charging current between the high voltage device and the low
voltage device, and regulate the total power to the energy storage
devices based on the determination.
Various other features and advantages will be made apparent from
the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate embodiments presently contemplated for
carrying out the invention.
In the drawings:
FIG. 1 is a schematic block diagram of an electric vehicle (EV)
incorporating embodiments of the invention.
FIG. 2 is a schematic diagram of a configurable multi-port charger
architecture according to an embodiment of the invention.
FIG. 3 illustrates an electrical schematic of a multi-port charger
according to an embodiment of the invention.
FIG. 4 illustrates a control scheme, as an example, specific to
module M2 of FIG. 2.
FIGS. 5 and 6 illustrate flow of a charging current in a multi-port
charger in exemplary modes of operation.
FIG. 7 is a table illustrating configurations as of the multi-port
charger illustrated in FIG. 2.
FIG. 8 is a block diagram illustrating a recharging scenario and
use of a communication interface, according to an embodiment of the
invention.
FIG. 9 illustrates control variables and parameters with respect to
a communication interface, according to an embodiment of the
invention.
FIG. 10 is a schematic block diagram of an electric vehicle (EV)
having an auxiliary power unit (APU) incorporating embodiments of
the invention.
FIG. 11 is a schematic block diagram of an electric vehicle (EV)
having an auxiliary power unit (APU) incorporating embodiments of
the invention.
DETAILED DESCRIPTION
FIG. 1 illustrates one embodiment of a hybrid electric vehicle
(HEV) or electric vehicle (EV) 10, such as an automobile, truck,
bus, or off-road vehicle, for example, incorporating embodiments of
the invention. In other embodiments vehicle 10 includes one of a
vehicle drivetrain, an uninterrupted power supply, a mining vehicle
drivetrain, a mining apparatus, a marine system, and an aviation
system. Vehicle 10 includes an energy storage and management system
(ESMS) 100 that is controlled by a controller or computer 46, an
internal combustion or heat engine 12, a transmission 14 coupled to
engine 12, a differential 16, and a drive shaft assembly 18 coupled
between transmission 14 and differential 16. And, although ESMS 100
is illustrated in a plug-in hybrid electric vehicle (PHEV), it is
understood that ESMS 100 is applicable to any electric vehicle,
such as a HEV or EV or other power electronic drives used to
operate pulsed loads, according to embodiments of the
invention.
According to various embodiments, engine 12 may be an internal
combustion gasoline engine, an internal combustion diesel engine,
an external combustion engine, or a gas turbine engine, as
examples. System 10 includes an engine controller 20 provided to
control operation of engine 12. According to one embodiment, engine
controller 20 includes one or more sensors 22 that are configured
to sense operating conditions of engine 12. Sensors 22 may include
an rpm sensor, a torque sensor, an oxygen sensor, and a temperature
sensor, as examples. As such, engine controller 20 is configured to
transmit or receive data from engine 12. Vehicle 10 also includes
an engine speed sensor (not shown) that measures a crankshaft speed
of engine 12. According to one embodiment, speed sensor may measure
engine crankshaft speed from a tachometer (not shown) in pulses per
second, which may be converted to a revolutions per minute (rpm)
signal.
Vehicle 10 also includes at least two wheels 24 that are coupled to
respective ends of differential 16. In one embodiment, vehicle 10
is configured as a rear wheel drive vehicle such that differential
16 is positioned near an aft end of vehicle 10 and is configured to
drive at least one of the wheels 24. Optionally, vehicle 10 may be
configured as a front-wheel drive vehicle. In one embodiment,
transmission 14 is a manually operated transmission that includes a
plurality of gears such that the input torque received from engine
12 is multiplied via a plurality of gear ratios and transmitted to
differential 16 through drive shaft assembly 18. According to such
an embodiment, vehicle 10 includes a clutch (not shown) configured
to selectively connect and disconnect engine 12 and transmission
14.
Vehicle 10 also includes an electromechanical device such as an
electric motor or electric motor/generator unit 26 coupled along
drive shaft assembly 18 between transmission 14 and differential 16
such that torque generated by engine 12 is transmitted through
transmission 14 and through electric motor or electric
motor/generator unit 26 to differential 16. A speed sensor (not
shown) may be included to monitor an operating speed of electric
motor 26. According to one embodiment, electric motor 26 is
directly coupled to transmission 14, and drive shaft assembly 18
comprises one axle or drive shaft coupled to differential 16.
A hybrid drive control system or torque controller 28 is provided
to control operation of electric motor 26 and is coupled to
motor/generator unit 26. An energy storage system 30 is coupled to
torque controller 28 and is controllable by ESMS 100. Energy
storage system 30 comprises a low voltage energy storage or energy
battery 32, a high voltage energy storage or power battery 34, and
an ultracapacitor 36, as examples. However, although a low voltage
energy storage 32, a high voltage energy storage 34, and an
ultracapacitor 36 are illustrated, it is to be understood that
energy storage system 30 may include a plurality of energy storage
units as understood in the art such as sodium metal halide
batteries, sodium nickel chloride batteries, sodium sulfur
batteries, nickel metal hydride batteries, lithium ion batteries,
lithium polymer batteries, nickel cadmium batteries, a plurality of
ultracapacitor cells, a combination of ultracapacitors and
batteries, or a fuel cell, as examples. An accelerator pedal 38 and
brake pedal 40 are also included in vehicle 10. Accelerator pedal
38 is configured to send throttle command signals or accelerator
pedal signals to engine controller 20 and torque control 28.
System 10 includes a charger interface 42 coupled to energy storage
units 32-36 of energy storage system 30 via ESMS 100, according to
embodiments of the invention. Charger interface 42 may be coupled
to multiple energy storage systems 32-36, as illustrated and
charger interface 42 may be coupled to one or multiple power input
lines 44, two of which are illustrated, according to embodiments of
the invention. ESMS 100 is configured to selectively engage and
disengage DC electrical devices or buck-boost modules as will be
discussed. In one embodiment and as will be illustrated, charger
interface 42 is connectable to a high voltage port of ESMS 100.
Typically, charger interface 42 includes an interface to the one or
more input lines 44 such that power from input lines is connectable
to a charging port of ESMS 100.
Although charger interface 42 is illustrated as being coupled to
energy storage systems 32-36 via ESMS 100, and charger interface 42
is illustrated as coupled to one or multiple power input lines 44,
it is to be understood that embodiments of the invention are not to
be so limited. Instead, it is to be understood that charger
interface 42 may be coupled to multiple and varying types of energy
storage systems and power inputs. Further, there may be multiple
charger interfaces 42 or ESMS units 100 per vehicle, or that there
may be power systems applied to each wheel 24 of vehicle 10, each
having a charger interface 42 coupled thereto.
In operation, it is understood in the art that energy may be
provided to drive shaft assembly 18 from internal combustion or
heat engine 12 via transmission 14, and energy may be provided to
drive shaft assembly 18 via drive control system 28 having energy
drawn from energy storage system 30 that may include energy systems
32-36. Thus, as understood in the art, energy may be drawn for
vehicle 10 boost or acceleration from, for instance a high voltage
storage device 34 that may include a battery, as an example, or
from ultracapacitor 36. During cruising (i.e., generally
non-accelerating operation), energy may be drawn for vehicle 10 via
a low voltage storage device such as low voltage energy storage
32.
And, during operation, energy may be drawn from internal combustion
or heat engine 12 in order to provide energy to energy storage 30,
or provide power to drive shaft assembly 18 as understood in the
art. Further, some systems include a regenerative operation where
energy may be recovered from a braking operation and used to
re-charge energy storage 30. In addition, some systems may not
provide regenerative energy recovery from braking and some systems
may not provide a heat engine such as internal combustion or heat
engine 12. Nevertheless and despite the ability of some systems to
re-charge energy storage 30, energy storage 30 periodically
requires re-charging from an external source such as a 115 V
household supply or a 230 V 3-phase source, as examples. The
requirement to re-charge energy storage 30 is particularly acute in
a plug-in hybrid electric vehicle (PHEV) having no heat engine to
provide power and an extended range of driving operation.
Thus, embodiments of the invention are flexible and configurable
having a plurality of energy ports, and may be coupled to multiple
power sources and source types in order to charge one or multiple
energy storage types. Further, embodiments of the invention allow
efficient and balanced charging of multiple energy systems 32-36 of
energy storage unit 30, the multiple energy systems having varying
levels of depletion.
To meet the demands of modern PHEVs and EVs, the infrastructure
should provide typically 7 kW to achieve a state-of-charge (SOC)
gain of 80% (assuming a 25 kWh battery) in a charging time of 2 or
3 hours (home charging). For a more aggressive short stop fast
charging scenario (e.g., a "gas station") significant higher power
levels may be required to achieve a desired 80% SOC in 10 minutes.
The vehicle interface needs to be designed according to existing
standards. A pilot signal determines by its duty cycle the maximum
allowable power. Besides a high degree of integration the proposed
system provides also single and or three phase AC input, high
efficiency, low harmonics, nearly unity input power factor, low
cost, low weight and safety interlocking of the equipment. The
power factor correction (PFC) requirement may be driven by
IEC/ISO/IEEE line harmonic current regulations, as known in the
art.
This invention is applicable to conventional electric vehicles
(EVs) as well as grid-charged hybrid electric vehicles (PHEVs).
Grid-charged HEVs provide the option to drive the vehicle for a
certain number of miles (i.e., PHEV20, PHEV40, PHEV60).
Traditionally, the goal for PHEVs is to provide a high
all-electric-range (AER) capability to lower operating cost and be
able to optimize the operating strategy. In terms of the buck-boost
stages, the charger front-end and interface, it generally makes
little difference if it is designed for an EV or PHEV application.
The role of the DC/DC converter is an efficient energy transfer
between two or more energy sources, reliable for continuous and
peak power demands. The integration of the charger unit is the next
step towards a higher power density design with fewer components
and therefore higher reliability. As such, embodiments of the
invention are applicable to multiple electric vehicles, including
all-electric and hybrid electric vehicles, as examples, designated
generally and broadly as "EV"s. Such EVs may include but are not
limited to road vehicles, golf carts, trains, and the like, capable
of having power systems that include an electric component for
causing motion of the vehicle.
In conventional implementations many separate units coexist, to
include generally a separate charger, battery management and
control unit that are interconnected. In an automotive environment
with advanced batteries, communications between the charger and
battery is an important consideration. In such environments
seamless integration with batteries from different battery vendors
is also an important consideration. The energy management system
with integrated charger is advantageous in that aspect that there
is less integration effort required and fewer components improve
reliability.
Referring now to FIG. 2, configurable multi-port integrated charger
architecture, energy storage and management system (ESMS) 100, is
generically illustrated having four energy ports 102 and three DC
electrical conversion devices or buck-boost converters respectively
as modules 1, 2, and 3 (104, 106, 108). As known in the art,
buck-boost converters 104-108 may be configured to operate in
either a buck-mode by flowing electrical energy therethrough in a
first direction 110 (illustrated with respect to buck-boost
converter 104, but equally applicable to converters 106 and 108),
or a boost mode by flowing electrical energy in a second direction
112 (illustrated again with respect to buck-boost converter 104,
but equally applicable to converters 106 and 108). As illustrated,
energy ports 102 comprise a first energy port P1 114 configurable
to have a first unit 116 attached or electrically coupled thereto.
Similarly, energy ports 102 comprise fourth, second, and third
energy ports P2 118, P3 120, and P4 122 that are configurable to
have respective second unit 124, third unit 126, and fourth unit
128 attached or electrically coupled thereto.
According to the invention the charger is part of the vehicle
design and mounted on-board. The integrated on-board charger is
capable of continuously adjusting input currents to energy ports
114 and 118-120 as a result of, for instance, varying SOC of
devices connected thereto for charging.
As will be illustrated, ESMS 100 of FIG. 2 may be configured to
charge up to three energy sources (to include low voltage energy
batteries, high voltage power batteries, ultracapacitors, as
examples) at the same time or simultaneously. ESMS 100 may have
modules therein configured to be interleaved in order to lower
ripple current. ESMS 100 also is capable of having multiple
charging profiles as a function of conditions that include SOC and
temperature, as examples, for different battery technologies and
storage device types. ESMS 100 includes a centralized energy flow
control that is centrally controlled by controller 46 of FIG. 1,
and ESMS 100 is capable of managing a wide range of input and
output voltages.
ESMS 100 of FIGS. 1 and 2 is configurable in multiple
configurations. Each configuration of ESMS 100 may be selectable by
contactors. Energy flow is controlled by ESMS control algorithms,
implemented in controller 46 of hybrid vehicle 10, which can sense
a presence of both energy storage devices and charging devices
connected to ports 102 and adjust a flow of direction of energy,
accordingly. For instance, the control algorithms may determine a
voltage of each port to which an energy storage device or an
electrical charging system (DC or rectified AC, as examples) is
coupled, and operate ESMS 100 accordingly and based on the
determined voltages, based on a measured frequency, or both (as
examples). And, a benefit for including a rectifier is that even if
DC is connected having the wrong polarity, the rectifier provides
protection, even if a single phase rectifier is used or if a DC
input is used to two of the 3-phase inputs for a 3-phase
rectifier.
The wide input voltage integrated charger allows independent and
simultaneous charging of two or more batteries of any SOC level
respectively from any input voltage level within the voltage limit
of ESMS components. The input voltage can range from typical single
phase voltages (110V/120V), to 208V/240V and up to 400V or even
higher (level 1 . . . 4). The highest currently specified voltage
is 400V for rapid DC charging, however with proper selection of
ESMS components, up to 480V single or 3-phase AC or even 600 V DC
can be utilized to provide higher level of charging for shorter
time duration (i.e., fast charging). An energy battery is either
connected to first energy port 114 or fourth energy port 118 and
has typically lower nominal voltages than the power battery on
second energy port 120. Short time energy storage devices, such as
ultracapacitors, may be included on first energy port 114.
Generically illustrated ESMS 100 of FIG. 2 may be configured by
selective use of switches in order to support a number of charging
arrangements. FIG. 3 illustrates a detailed circuit diagram of a
multi-port ESMS according to an embodiment of the invention. For
simplicity, control electronic components are omitted. Thus, ESMS
200 (similar to ESMS 100 of FIGS. 1 and 2) illustrates a first
buck-boost module 202, a second buck-boost module 204, and a third
buck-boost module 206. ESMS 200 also illustrates port P1 208 having
a relatively low voltage battery coupled thereto, port P2 210
having a relatively high voltage unit coupled thereto, port P3 212
having a rectified AC or DC voltage coupled thereto, and port P4
214 having a relatively low voltage ultracapacitor coupled thereto.
Thus, in the example illustrated, energy storage devices and an
energy charger are coupled to ESMS 200 in order to illustrate
operation according to one configuration. However, as discussed,
ESMS 200 may be configured in numerous arrangements in order to
accommodate multiple charger/energy storage arrangements. As such,
ESMS 200 includes contactors K3 216, K1 218, K2 220, K4 222, and M
224 which may be selectively engaged or disengaged in order to
accomplish configurations for charging, according to the
illustrations above.
Each of the three buck-boost modules M1 202, M2 204, M3 206
includes an IGBT leg (upper and lower switch) and an inductor. The
high voltage DC bus may be buffered by a number of power
capacitors. Each buck-boost converter stage output is equipped with
a current sensor, which measures an inductor current. Voltage
limits shown at port P3 212 are originated by typical single-phase
AC outlet voltages in both the US and Europe. However, in
applications requiring higher levels of charge power, port P3 can
be coupled via charger interface 42 (FIG. 1) to 208V, 240V, or 480V
3-phase, or either 400 V DC or up to 600 V DC.
ESMS 200 uses contactors as main bus and individual module
switches. A pre-charge circuit is realized using two power
resistors (e.g., 120 ohm, 100 W, RH-50) and a contactor or FET. An
additional contactor (K4 222 in FIG. 3) serves in two cases. One is
under a certain SOC condition of a battery at port P1 208, and the
second if interleaving of module 1 202 and module 3 206 is enabled.
FIG. 3 illustrates voltage and current sense points of ESMS 200
having an integrated charger.
Charging may be using a single battery or a dual battery. Charging
in a dual battery configuration as shown here allows charging from
a wide input voltage range of batteries with an arbitrary SOC level
for both batteries. The internal architecture of the multi-port
integrated charger with its software features only allows this.
Upon power-up, ESMS 200 control recovers the type of energy storage
units that are being used, their energy ratings and limits for
charging current and power. From the communication interface to the
electric vehicle supply equipment (EVSE) the ESMS sets limits for
input current and eventually the type of power source (AC or
DC).
Each buck-boost module runs an independent state machine. The
states are disabled/standby, buck mode enabled, boost mode enabled
or enabled permanent conducting upper switch (specific to module 2
204 as illustrated in FIG. 4 as sequence 250). Module state
selection occurs at step 252 and power on self-test occurs at step
254. Input voltage range is determined at step 256 and if V.sub.min
and V.sub.max are on the high side 258, then switch K1 218 is
closed and module M2 204 is enabled 260, causing module M2 204 to
operate in buck mode. If V.sub.min and V.sub.max are on the low
side 262, then switch K1 218 is opened and module M2 upper switch
is on, causing module M2 204 to be permanently on 264. At step 266,
module M1 202 is requested and the state of module M2 204 (i.e.,
buck mode at step 202 or permanently on at step 264) is returned at
step 268 for further operation. Part of this sequence is also to
force the contactors into the right state. For charging generally
contactor K3 216 is closed to allow the use of modules M1 202 and
M2 204 for controlled charging of the port P2 210 energy storage
device. In this sequence of the charging control the software
distinguishes several cases that might apply and selects the
appropriate state of each of the three buck-boost modules
202-206.
In the start-up sequence and before any contactor is forced to the
ON state and before the modules and switching of the IGBTs are
enabled, ESMS 200 control acquires the voltage levels of all used
energy sources and determines the charger input voltage. This is
done in order to avoid any possible uncontrolled current when for
example the voltage on the low side of the buck-boost module is
higher than the voltage on the high side. This can be the case for
example when the power battery on the high side is deeply
discharged and the energy storage devices on port P1 208 and/or
port P4 214 still have a significant amount of energy stored. This
is a scenario that is typically avoided by normal operation energy
management of the vehicle, but it might be possible if the high
side energy storage device is replaced and not charged up prior to
replacement, or the normal operation energy management was not
active for long time for some reason. The integrated charger
control can handle even very extreme and unusual voltage levels at
all four ports 208-214 and allows controlled energy management to
bring the system back to normal operation.
In one mode of operation, referring to FIG. 5, a charging current
is established into the high side energy storage device at port P2
210. This is referred to as the single HV battery charging mode.
Module M1 202 operates in boost mode, contactors K3 216 and M 224
are closed, while contactors K1 218, K2 220 and K4 222 are open.
Depending on the charger input voltage, module M2 204 is in buck
mode (V.sub.P3>V.sub.P2) or the upper switch is permanently
conducting (V.sub.P3<V.sub.P2). The charging current is
controlled through module M1 202. Depending on the charging
strategy, the SOC or the voltage level of the device at port P2 210
the control determines the charging current and the time of
operation in this mode.
As an extension to the mode described before, referring to FIG. 6,
the charger control enables charging of a second energy storage
device on either port P1 208 or port P4 214. This may be referred
to as a dual battery charging mode. In this mode the control
ensures that a controlled current flow is possible before closing
the contactors and enabling module M3 206. If the voltage levels
are in permissible range either contactor K2 220 or K4 222 are
forced into ON state, module M3 206 is set into buck mode and
determines the charging current and the time of operation in this
mode. An initial power split factor is applied while currents and
voltages are constantly monitored to calculate each individual SOC.
By using a commercial off the shelf (COTS) battery pack, the
standardized communication interface of the integrated charger ESMS
also allows to receive voltage and SOC from the system. The
integrated charger ESMS executes the desired charging strategy,
which depends on battery technology, thermal constraints, etc.
SOC of attached energy storage devices is estimated to determine a
power split from the wide voltage input to the energy storage
devices. Individual device SOC is constantly monitored to determine
and optimize the power split factor. This task is responsible for
handling extreme SOC levels appropriately. For example, a fully
discharged high side battery on port P2 210 might operate at
voltages that are below the battery on port P1 208. In this case
charging up the high side battery on port P2 210 is required before
a charge power split can be performed.
Referring to FIGS. 5 and 6, energy flow for two configurations of
charging is illustrated. Referring first to FIG. 5, energy is to
flow from a charger (not illustrated) positioned on port 3 212, to
module 2 210, and to module 1 208 operating in boost mode. As such,
a DC source may be boosted to a high-voltage output on port 2 210,
by ensuring K1 218 and K2 220 are open.
In the other example illustrated in FIG. 6, port 1 208 and port 4
214 may be charged simultaneously from a DC source (not shown)
coupled to port 3 212. Two cases may be considered regarding FIG.
6, as examples.
Case 1: Input voltage at port 3 212 is higher than battery voltage
at port 1 208. In this case module 2 204 operates in buck mode and
the current ILB in LU is regulated. Contactors K3 216 and K1 218
are closed, while M 224, K2 220 and K4 222 (UPOS) are open.
Case 2: Input voltage at port 3 212 is lower than battery voltage
at port 1 208. In this case contactors K3 216, M 224 and K4 222
(UPOS) are closed, while K1 218 and K2 220 are open. Module 2 204
is inactive (M2 is permanently on), module 1 202 operates in boost
mode to boost the low input voltage up to some higher level. Module
3 206 bucks this voltage back to the set voltage of the energy
battery at port 1 208. The current ILC in LW is controlled in a
closed loop fashion.
Thus, FIGS. 5 and 6 illustrate different charging scenarios that
may be implemented using ESMS 200 of FIG. 3, illustrating as well
the direction of current flow corresponding to the charging
arrangement illustrated. However and as stated, ESMS 200 may be
used in multiple configurations. Different energy storage types and
chargers may be connected to ESMS 200 according to embodiments of
the invention, as illustrated in FIG. 7 as a table 300. That is,
exemplary charging scenarios 1-5 302 include functions 304 and the
various charger and energy storage devices positioned at ports 1-4.
It is contemplated that, although five charging scenarios 302 are
illustrated, the invention is not so limited and any
charger/storage arrangement is possible.
Referring now to FIG. 8, an exemplary charging arrangement is
illustrated that corresponds generally to charging scenario 3 of
Table 300 of FIG. 7. The configuration illustrated in FIG. 8,
configuration 400, is illustrated having ESMS 200 with ports P1
208, P2 210, P3 212, and P4 214. Configuration 400 is illustrated
in order to show communication interface 402 and its operation. An
energy battery or ultracapacitor 404 is coupled to port P1 208, an
ultracapacitor or energy battery 406 is coupled to port P4 214, and
a power battery 408 is coupled to port P2 210. An AC or DC source
410 is coupled to port P3 212 and, as stated above, may be coupled
through a charger interface 42 of FIG. 1. Communication interface
402 is coupled to storage devices 404-408, as well as source 410,
according to embodiments of the invention. Communication interface
402 is also illustrated in FIG. 1, in communication with energy
storage 30 (having devices 30-36), controller 46, and charger
interface 42.
Referring still to FIG. 8, communication interface 402 includes
multiple communication lines 412, 414, 416, and 418 coupled thereto
which enable sensor readings to be carried from respective devices
404-410. That is, communication lines 412-418 are coupled to their
respective device in order to obtain temperature limits and current
limits, as examples, that pertain to devices 404-410, as well as
provide realtime feedback regarding temperature, current, and
voltage, of each respective device 404-410. Additionally, device
parameters such as current state-of-charge and voltage measurements
may be obtained as well from each device 404-410.
Thus, referring to FIG. 9, communication interface 402 is
configured to receive multiple inputs from various sources in order
to optimize charging operation, according to the invention.
Communication interface 402 is coupled to controller 46, which is
configured to output two parameters 420, according to the
invention. Two parameters 420 include an overall charging current
422 and a power split 424. That is, based on information received
from, and regarding the current state of devices 404-410, overall
charging current 422 and power split 424 are determined and fed to
ESMS 100 in order to optimize regarding of devices 404, 406, and
408, according to embodiments of the invention.
As seen in FIG. 9, communication interface 402 receives a number of
types of information pertaining to devices 404-410. For instance,
communication interface 402 receives limit information 426 that
includes but is not limited to temperature limits of each of the N
devices (i.e., devices 404-410), maximum current pertaining to
each, or maximum rate of current change, as examples. Communication
interface 402 also receives energy storage device parameters 428
for each of the N devices 404-410 as well. Parameters 428 include
but are not limited to a state-of-charge (SOC), a minimum voltage,
and a maximum voltage, as examples. Communication interface 402
also receives sensor feedback 430 from each of the N devices
404-410, which includes but is not limited to current in each
device, voltage across each device, and temperature of each
device.
Thus, communication interface 402 receives limit information 426,
device parameter information 428, and realtime sensor information
430 which are processed and fed to controller 46 such that overall
charging current 422 and power split 424 may be determined therein
and fed to ESMS 100. ESMS 100 thereby and in turn controls modules
M1-M3 therein accordingly. According to one embodiment of the
invention, power split 424 is split between high and low voltage
sides of ESMS 100 (high voltage side includes ports P2 210 and P3
212, while the low voltage side includes port P1 208 and P4 214).
That is, referring to FIG. 8 for instance, power split 424 includes
a percentage of total power that is directed toward power battery
408, and the remaining percentage of total power that goes to both
storage device 404 and storage device 406. Thus, in an embodiment
where only one low voltage storage device is coupled to the low
voltage side of ESMS 200, and one high voltage storage device is
coupled to the high voltage side of ESMS 200, then power is split
fractionally to the low and the high voltage storage devices, and
the total current to both devices is controlled, accordingly.
According to the invention, power regulation to the low and high
voltage sides is continuous based on a continuous monitoring of the
sensors. According to one embodiment, if one of the low or high
voltage storage devices is fully depleted, then when beginning to
charge the low and high voltage storage devices, the power split is
100% to the fully depleted device, after which monitoring as
described dictates a continuous revision of total power and power
split, as described.
According to the invention, controller 46 may apply thermal
balancing by controlling operation of a fan based on feedback,
temperature limits, etc. . . . . Thus, referring back to FIG. 1, a
fan 432 may be positioned to blow air over one or all of the energy
storage devices (32-36) shown therein, which likewise correspond to
the energy storage devices 404-408 of FIG. 8 or energy storage
devices 208, 214, and 210 of FIGS. 5 and 6. Temperature information
is usually available from the different energy storage units that
can be used to provide a coarse thermally balanced charging that is
achieved by splitting the power flow symmetrically over all
modules. In a scenario of at least one Li-Ion battery pack in the
system, especially if passive balancing is applied, temperature
information is usually available to be used by the charging
control. A thermal model can be used if the sensor distribution is
coarse or the battery technology allows easy prediction of the
temperature distribution inside the pack. Thus, for thermal
balancing the control objective is to balance battery pack
temperature distribution and, in addition to controlling total
current 422 at port P3, and power split 424 between units, fan
operation can be controlled as well using fan speed control,
thermal modeling, and the like, in order to optimize thermal
performance of the energy storage devices.
According to the invention, power may be maximized to the high
voltage side (i.e., the power battery). The objective of this
charging strategy is to bring the DC link voltage up rapidly and
utilize fully the available power to charge the power battery. This
might be desired if there are shorter discharge and charging cycles
desired or possible. Therefore a more frequent recharging is
performed by the high performance power battery, both the DC link
voltage is kept relatively high and boosting energy from the second
battery is avoided to improve efficiency. Thus, in this scenario
the control objective is to maximize a state-of-charge at port P2
on the high voltage side and in the power battery in the shortest
amount of time, in addition to controlling total current 422 at
port P3, and power split 424 between units.
According to the invention, depending on the dual battery
configuration (e.g., power battery and energy battery of similar
capacity), it may be desired to keep the energy balanced within the
dual battery configuration during charging. The state-of-charge
levels of both batteries that are available to the integrated
charger energy management are controlled to be on equal levels
within an acceptable error. Thus, in this scenario the control
objective is to maintain the state of charge (SOC) at both ports P1
and P2 at a similar level, and further to rise their respective SOC
with a similar slope, by controlling total current 422 at port P3,
and power split 424 between units.
According to the invention, by using Li-Ion battery technology,
where cell groups need to be individually balanced, due to aging
temperature effects or discharge rates, the individual cell groups
might be imbalanced significantly. An optimal pack balancing
strategy includes keeping minimum and maximum cell voltages within
a limit. A subsequent control uses available energy to charge a
lesser constrained battery of a different technology. However, an
imbalanced Li-Ion battery pack usually requires long charging times
since active or passive balancing is time consuming while the
charging current has to be reduced significantly and over a long
period. Thus, in this scenario the control objective includes
minimizing a voltage gap between maximum and minimum cell voltages
of both batteries, such as at ports P1 and P2, by controlling total
current 422 at port P3, and power split 424 between units.
According to the invention, minimizing losses and therefore
maximizing efficiency of the overall system is a goal, and many
parameters need to be considered during the design of the DC-to-DC
converter and the boost inductors. Once the multi-port buck-boost
converter design is finalized, loss optimized control can be
achieved for example through operating the converter predominately
in a range of high efficiency. This is in many cases around rated
power rather at light load, where efficiency usually drops. Also if
a small discharge cycle can be assumed, for example in a <40
mile daily commute mode is selected, the use of the boost can be
limited to the absolute necessary during driving operation. The
capability of the battery providing power is based on the history
of charge and discharge cycles. A high C-rate operation strategy
has an impact on the internal resistance and causes faster aging.
With that an efficiency optimized operation strategy is linked to a
lifetime optimized strategy to some degree. Thus, in this scenario
the control objective is to operate at maximum of the efficiency
curves, obtained by controlling total current 422 at port P3, and
power split 424 between units.
Thus, numerous control schemes and optimization scenarios are
included, which may be optimized according to embodiments of the
invention. Examples given include but are not limited to thermal
balancing, maximizing power to the high voltage side (power
battery), balancing state-of-charge levels, optimal pack balancing,
and loss minimized control.
Source 410 of FIG. 8 includes an AC or a DC source 410 that is
coupleable to ESMS 200 during periods when vehicle 10 is parked
(such as at a charging station, at home in a garage, or during
work, as examples). However, the invention is not necessarily
limited to charging when vehicle 10 is stationary. That is,
according to the invention, an auxiliary power unit (APU) may be
included that is positioned on vehicle 10 that enables energy
storage system re-charge as well as providing power for vehicle
operation. Referring to FIG. 10, vehicle 10 in this embodiment
includes an APU 500 in lieu of the energy battery 404 of FIG. 8.
Thus, consistent with vehicle 10 of FIG. 1, vehicle 10 may include
in addition to heat engine 12, an APU that provides auxiliary power
to electric motor 26 via ESMS 200 (also labeled as ESMS 100 in FIG.
1). APU 500 may include an internal combustion engine (ICE), a
permanent magnet generator (PMG), or a fuel cell (FC), as examples.
That is, in lieu of a low voltage/high energy, energy storage
system such as LV supply 32 of FIG. 1, APU may provide electrical
power to system 10 via ESMS 200 to provide power for vehicle
cruising, or to provide power for re-charge of other energy storage
units 406, 408. For instance, in one mode of operation, heat engine
12 may provide power to electric motor 26 to provide power for
vehicle operation, while at the same time, APU 500 can provide
re-charging energy to energy storage units 406, 408. In such
fashion, energy use can be optimized by selectively providing power
from heat engine 12 and re-charging other storage units for peak
efficiency. The APU 500 provides additional flexibility of
operation and enables independent or simultaneous charging of both
batteries 406, 408, and extends the integrated charging control.
Charging is no longer limited to stationary charging.
In another embodiment of the invention, referring to FIG. 11,
vehicle 10 includes APU 500 positioned thereon that is switchably
coupleable to port P3 212. That is, APU 500 is an auxiliary unit
positioned on vehicle 10 but, instead of being coupled to ESMS 200
via port 1 208 as in FIG. 10, APU 500 is coupled to port P3 212 via
a switching device 502. Thus, according to this invention, instead
of having port P1 208 dedicated to providing power from APU 500,
port P1 208 may be dedicated to coupling an energy battery or an
ultracapacitor 404 as in previous illustrations, and port P3 212
may be used for providing charging from a stationary source 410 as
well as providing auxiliary power during vehicle operation. That
is, by coupling APU 500 through charging port P3 212, additional
flexibility of operation is provided because energy can be drawn
for vehicle operation via heat engine 12, energy batteries 404,
406, power battery 408, as well as from APU 500. When stationary,
switching device 502 may be switched to enable re-charge from a
stationary source 410.
Thus, overall charging control can be extended beyond a stationary
case where AC/DC power is provided from the grid via stationary
supply 410. Charging control strategies can be centralized, which
allows interoperability of different battery chemistries on one
electric vehicle system. That is, because of the sensor feedback,
limit information for specific battery types and energy storage
types, and because of the ability to obtain and use device
parameter information in realtime during vehicle operation, system
flexibility is improved and efficiency is optimized, which is all
provided through a single centralized energy storage and
managements system.
A technical contribution for the disclosed apparatus is that it
provides for a controller implemented technique of charging energy
storage devices of an electric vehicle using a multiport energy
management system, based on system feedback.
One skilled in the art will appreciate that embodiments of the
invention may be interfaced to and controlled by a computer
readable storage medium having stored thereon a computer program.
The computer readable storage medium includes a plurality of
components such as one or more of electronic components, hardware
components, and/or computer software components. These components
may include one or more computer readable storage media that
generally stores instructions such as software, firmware and/or
assembly language for performing one or more portions of one or
more implementations or embodiments of a sequence. These computer
readable storage media are generally non-transitory and/or
tangible. Examples of such a computer readable storage medium
include a recordable data storage medium of a computer and/or
storage device. The computer readable storage media may employ, for
example, one or more of a magnetic, electrical, optical,
biological, and/or atomic data storage medium. Further, such media
may take the form of, for example, floppy disks, magnetic tapes,
CD-ROMs, DVD-ROMs, hard disk drives, and/or electronic memory.
Other forms of non-transitory and/or tangible computer readable
storage media not list may be employed with embodiments of the
invention.
A number of such components can be combined or divided in an
implementation of a system. Further, such components may include a
set and/or series of computer instructions written in or
implemented with any of a number of programming languages, as will
be appreciated by those skilled in the art. In addition, other
forms of computer readable media such as a carrier wave may be
employed to embody a computer data signal representing a sequence
of instructions that when executed by one or more computers causes
the one or more computers to perform one or more portions of one or
more implementations or embodiments of a sequence.
According to one embodiment of the invention, an electric vehicle
includes a controller configured to receive sensor feedback from a
high voltage storage device and from a low voltage storage device,
compare the sensor feedback to operating limits of the respective
high and low voltage storage device, determine, based on the
comparison a total charging current to the high voltage storage
device and to the low voltage storage device and a power split
factor of the total charging current to the high voltage device and
to the low voltage device, and regulate the total power to the low
voltage storage device and the high voltage storage device based on
the determination.
In accordance with another embodiment of the invention, a method of
managing an energy storage system for an electric vehicle includes
receiving sensor feedback from a high voltage energy storage device
of the electric vehicle, comparing the sensor feedback from the
high voltage energy storage device to an operating limit specific
to the high voltage energy storage device, receiving sensor
feedback from a low voltage energy storage device of the electrical
vehicle, comparing the sensor feedback from the low voltage energy
storage device to an operating limit specific to the low voltage
energy storage device, determining, based on the comparison from
the high voltage device and from the low voltage device a total
charging current to the high voltage storage device and to the low
voltage storage device and a power split factor of the total
charging current to the high voltage device and to the low voltage
device, and regulating the total power to the low voltage storage
device and the high voltage storage device based on the
determination.
In accordance with yet another embodiment of the invention, a
computer readable storage medium coupled to an energy storage and
management system (ESMS) of an electric vehicle (EV) and having
stored thereon a computer program comprising instructions which
when executed by a computer cause the computer to receive sensor
feedback from a high voltage energy storage device of the EV and
from a low voltage energy storage device of the EV, compare the
sensor feedback to operating limits of the respective energy
storage devices, determine, based on the comparison a total
charging current to the energy storage devices and a power split
factor of the total charging current between the high voltage
device and the low voltage device, and regulate the total power to
the energy storage devices based on the determination.
This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in
the art to practice the invention, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal languages
of the claims.
While the invention has been described in detail in connection with
only a limited number of embodiments, it should be readily
understood that the invention is not limited to such disclosed
embodiments. Rather, the invention can be modified to incorporate
any number of variations, alterations, substitutions or equivalent
arrangements not heretofore described, but which are commensurate
with the spirit and scope of the invention. Additionally, while
various embodiments of the invention have been described, it is to
be understood that aspects of the invention may include only some
of the described embodiments. Accordingly, the invention is not to
be seen as limited by the foregoing description, but is only
limited by the scope of the appended claims.
* * * * *